Cellular rubber chloride



Marchl3, 1945- I G. R. cuTHBERTsoN 2,371,382-' I CELLULAR RUBBER CHLORIDE Filed April 28, 1942 MW (aff-@Rf H54 m15/ 'roamed Mio. 1-3, 1945 artista CELLULAR HUBER C iii-1f. il

George R. Cuthbertson, Detroit, Mich., assior to United States Rubber Company, New

York,

N. Y., a corporation of New Jersey l Application April 2s, i942, sol-iai No. orosei (ci. lmet) 2 claims.

desired shape and of somewhat greater s ize, and

is heated to a temperature or temperatures in the range from about 300 F. vto about 350 F.,

evolution of volatile products takes place within the interior of the mass to such` an extent that `the rubber chloride expands and substantially completely fills the mold, and the rubber chloride is obtained in an expanded closed-cell form provided that the mold .is kept closed until the rubber chloride has cooled below its hardening' temperature.' The shape of the expanded mass is determined by the shape of the mold.

Powdered vrubber chloride does not permit such a result; the total surface of the powder is so great, relative to its bulk, that substantially all the volatile products evolve from the surface of the material and hence exert no expanding ef-V fect. It has therefore been found to be necessaryto the present process to use relatively large or coarse pieces of rubber chloride, i. e., pieces comparable in size to one-quarter-inch cubes, rather than finely divided material. The less the number of pieces, the stronger the bonding with# in the nal piece. Preferably, a large single piece oi' rubber chloride should be used to load each mold. The. piece-or assembled -pieces should.

preferablyybe so approximately shaped s to be Eeometrically, similar ,to the nal piece desired. Preferably, Aeach dimension of the original piece of rubber chloride placed in the mold should be 1 approximately one-half of the corresponding di- Lmention ofthe iinal expanded object.

Fig. 1 of the drawing represents a cross-sec- F' tion' in plan 'of the assemblyof mold and rubber chloride mass before heating; and

Fig. 2 represents a. similar cross-section showingthe condition in the inold after heating.

Rubber chloride herein is to be understood as including the-commercial material as Well as large proportions of the same with plasticizers, llers, or diluents. A

An advantage of expanded rubber chloride is that it is substantially fire-proof and may be used for all purposes where gas-expanded hard rubber is used.

It will be apparent to those skilled in the art that modifications may be made in the amounts of material and nature of the rubber chloride, with consequent variation in temperatures eective to blow the material, without departing from the principles of the invention as covered by the appended claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A process for producing an expanded rubber chloride product winch comprises placing a mass of non-powdered irubber chloride in a mold oi the shape of the desired article, said mass being smaller than the mold cavity but sulcient to fill the cavity upon expansion, heating the mass to a temperature in the range from about 300 F.

to about 350 F. until the gases evolved lfrom the rubber chloride per se at said temperature expand said mass to iill the mold, discontinuing the heating and maintaining the mold closed until the .rubber chloride has cooled below its hardening temperature before removing the same from the mold. y

2. A process for producing an expanded'rubber chloride product which comprises placing ilu.l a mold of the shape of the desired article, a massl of Anon-powdered rubber chloride composed of a piece or pieces of selectively large size sufficient to permit expansion thereof by evolved gas from the rubber chloride per -se on heating, said mass being smallerthan the mold cavity but suiilcient to ll thelcavity upon expansion, heating' the mass to a temperature in the range from about 300 F. to about 350 F. until the said evolved gases expand saidJ mass to ll the mold,- discontinuing the heating vand maintaining the mold olosod until the rubber' chloride has oooledbelow its hardening temperature before removingthe same from the mold.

GEORGE a. CU'rrusllzrrrsonl 

